1. Field of the Invention
The present invention relates to a method for retrieving related word information, an information processing apparatus employing this method, a method for controlling related information display, and a related information display apparatus employing this method.
2. Description of the Related Art
In a conventional information retrieval system, when the user inputs a word into the system to retrieve information related to the word (hereinafter, such information is referred to as related word information) from a database, the following procedure is normally conducted: upon receipt of a word from the user, the system determines the level of the relationship (relation level) between the input word and another word (related word) or the relation level between the input word and information related to the input word (related information) by calculating a predetermined expression or referring to an information table and the like and making a list of related words sorted from a word with a higher relation level to a word with a lower relation level.
Japanese Laid-Open Patent Publication No. 5-233717 and No. 5-233718 disclose information retrieval apparatuses which calculate the relation level between information input by the user and information stored in a database, and, on receipt of a relation level input by the user, displays information corresponding to the input relation level.
With the recent enhancement in the performance of computers, the amount of data handled by computers has become enormous. When an information retrieval system used in such a computer retrieves data from an enormous database, the amount of resultant retrieved data tends to be large.
In conventional information retrieval systems, large a mounts of retrieved data are displayed in the following exemplified manners. A scroll bar is provided on the portion of a display screen where the retrieved results are displayed to allow the user to scroll the list of retrieved results. Alternatively, a multi-stage menu method is adopted, where each retrieved result is divided into a plurality of groups, each group further divided into a plurality of parts, wherein a plurality of parts being displayed as a group unit.
However, in such conventional information retrieval systems the listing of retrieved results is so ineffective that the work required to search a desired information item is inefficient.
The above problem may be solved to some extent by the method disclosed in aforementioned Japanese Laid-Open Patent Publication No. 5-233717 and No. 5-233718, where only items corresponding to the relation level specified by the user are displayed. However, there is a possibility that a retrieved information item desired by the user may not be included in the displayed information items corresponding to the relation level specified by the user. Therefore, this method is not a substantial solution of the problem.
Conventionally, in related information display apparatuses used for document edit processing systems such as wordprocessors and computer systems, in order to display information related to an information unit displayed on a display screen, the user must discontinue the current work to follow a procedure for retrieving related information and displaying the retrieved information.
For example, in document edit processing systems such as wordprocessors, there has been a system developed where appended information can be edited on a memo screen, and the like, the edition of original document information. In such a system, the original document and the document on the memo screen are handled separately. Therefore, in order to display the appended information, the user must input an instruction to display the appended information on the memo screen.
As another example, an application program has been developed where detailed information on an information unit displayed on a display screen can be displayed by menu selection at any time. To use this function, the user must take some intentional action, that will result in the discontinuation of the current work on the original screen.
Japanese Laid-Open Patent Publication No. 3-10368 proposes an appended information display processing method to improve the above troublesome operation required for displaying appended information. In this method, a unit of document information is stored together with corresponding appended information. The system determines whether or not an information unit on a display screen indicated by a cursor has its corresponding appended information, and if it has, displays the appended information on an appended information display region of the display screen.
However, in the above method, since the appended information needs to correspond to a certain information unit of the document (e.g., a word), general information such as dictionary information and address information cannot be used. Therefore, only related information linked to a certain information unit of the displayed document can be obtained, and thus the range of retrieval is narrow. If more detailed retrieved information is desired, a larger amount of related information must be stored for every information unit of the document displayed. Further, in this method, appended information linked to a certain information unit of the document indicated by the cursor is retrieved. Therefore, since the detection of information is restricted to the linked information, the application thereof is restricted.